Quiz 1

Question 1

Who is Thomas Hunt Morgan?

Answer 1

• geneticist
• discovered first mutant (white eye)
• established theory of chromosomal linkage

Question 2

Why is D. Melanogaster a convenient research organism?

Answer 2

• short life cycle
• easily cultured
• small size
• large enough
• abundant gene variability
• inexpensive

Question 3

What are the phenotypic difference between males and female flies?

Answer 3

Female: larger
Males: spiky hairs surrounding anus and genitals, black abdomen

Question 4

Abdomen

Answer 4

Third body segment

Question 5

alula

Answer 5

fringed flap at posterior base of wing

Question 6

halteres

Answer 6

vestiges of second pair of wings; also known as balancers

Question 7

ocelli

Answer 7

three small eyes dorsal-medial to compound eyes

Question 8

sex combs

Answer 8

structure on first tarsal segment of first pair of legs in males only

Question 9

sternite

Answer 9

ventral abdominal segmental plate

Question 10

tarsus

Answer 10

distal leg segments

Question 11

tergite

Answer 11

dorsal abdominal segmental plate

Question 12

thorax

Answer 12

body segment between head and abdomen

Question 13

medial

Answer 13

toward the center

Question 14

distal

Answer 14

toward the end

Question 15

dorsal

Answer 15

toward the back

Question 16

ventral

Answer 16

toward the belly

Question 17

what are the four distinct stages in the life of a fruit fly?

Answer 17

egg, larva, pupa, and adult

Question 18

Time it takes fruit fly to mature from egg to adult?

Answer 18

10 days at 25 degrees, 20 days at 18 degrees

Question 19

How long does it take after eclosure for males and females to mate?

Answer 19

male: at least 12 hours
female: at least 8 hours

Question 20

At 25 degrees, how long does fly spend in each development stage?

Answer 20

Egg/embryo: 1 day

larva: 1 then 3 days
pupa: 4 days

Question 21

How is the fly genome organized? What is it’s size?

Answer 21

• 4 pairs of chromosomes
• Chr 1: sex chromosome (males are hemizygous)
• Chr 2,3, and 4: autosomal (Chr 4 very few genes)

Question 22

What is the difference between a linkage map and a cytogenic map?

Answer 22

• linkage map: data that represents distance between genes based on expected frequency of recombination
• cytological map: physical map based on banding pattern of polytene chromosomes

Question 23

What are some rules of genetic nomenclature?

Answer 23

1. concise gene names
2. unique
3. lowercase letter for mutant gene of mutant phenotype recessive in heterozygote
4. uppercase letter for mutant that is dominant to wild type phenotype
5. names or symbols of genes italicized, phenotype or gene product not.

Question 24

Phenotypic mutants

Answer 24

can affect any body part

Question 25

biochemical mutants

Answer 25

mutations that render enzymes or proteins defective

Question 26

homeotic mutants

Answer 26

development mutations result in relocation of body parts from normal position

Question 27

chromosomal aberrations

Answer 27

results when pieces of chromosomal material are altered in various ways

Question 28

What is kept in a balanced stock?

Answer 28

Homozygous lethal genes

Balanced stock is one that regenerates same heterozygotes

Question 29

What were the two possible hypotheses to account for passing of traits?

Answer 29

1. particulate- parents pass on discrete heritable units (genes)
2. blending- genetic material from two parents blends together

Question 30

What are alleles?

Answer 30

Alternate versions of a gene

Question 31

What is the purpose of a reciprocal cross?

Answer 31

two crosses used to determine the mode of inheritance of a gene (autosomal vs. sex-linked)

Question 32

What is a 1-point cross?

Answer 32

a cross involving only one trait

Question 33

What is a monohybrid cross?

Answer 33

a 1-point cross where both parents are heterozygous

Question 34

What is the law of segregation?

Answer 34

the two alleles of a gene separate during meiosis and end up on different gametes

Question 35

What is the law of independent assortment?

Answer 35

each pair of alleles segregates independently of each other pair of alleles during gamete formation

Question 36

What is the identifier for a virgin female fly?

Answer 36

-black spot on abdomen known as the meconium

Question 37

What is expressivity?

Answer 37

degree to which a trait is expressed

Question 38

What is penetrance?

Answer 38

measures the proportion of individuals in a population who carry a specific gene and express the related trait